Depolymerization of bituminous coal utilizing friable metal reactants



Nov. 1

COAL

J. WINKLER FRIABLE METAL REACTANTS Filed April 30, 1963 COAL+ZlNC DUST l 4' 4 v, A:

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JOSEPH WINKLER ATTORNEY S United States Patent 3,282,826 DEPOLYMERIZATION OF BITUMINOUS COAL UTILIZING FRIABLE METAL REACTANTS Joseph Winkler, 5707 Hemlock St., Sacramento, Calif. Filed Apr. 30, 1963, Ser. No. 277,422 19 Claims. (Cl. 208-8) This invention rel-ates to anew process of depolymerization of bituminous coal and products derived therefrom, wherein a solid-solid reaction between coal particles and particles of a friable, solid metal, metal mixtures and/or alloys thereof; said metals being distinguished by good reactivity with oxygen and sulphur atoms, is induced and effected by heat generating grinding of said mixture, thereby leading to the cleavage of the coal macromolecule between the O 0 C and -G S C molecular bridges. The expression grinding operation is being used in the generic sense and covering repetitious, intimate surface frictional contact of the coal with the metal particles, as well as a more vigorous mutual abrading action resulting in a continuous reduction of the coal and metal particle size.

The well known prior art teaches that bituminous coals can be partially converted into liquid products by heating to temperatures up to 1000 C., the main macromolecular cleavage occurring between the linkages. In the coal hydrogenation process, the heat treatment of the coal in addition is conducted at temperatures 450-480 C. and under high pressure up to 700 atm. of gaseous hydrogen, which, by combining with the heat generated radicals helps to stabilize them, thus preventing their repolymerization into solid carbonaceous materials of low value.

It follows that in both aforementioned coal processing methods, the main reaction can be characterized by two general equations:

and in hydrogenation;

wherein R and R are various hydrocarbon type molecular structures, and x=m+n.

On the other hand, the distinguishing feature of my invention is twofold:

(1) First, it radically differs in the processing methods applied, the main characteristic being a self-heat generating grinding process, later described in the examples.

(2) Secondly, by the utilization of metals having a predominant affinity to oxygen and sulphur atoms, the cleavage of the coal macromolecule is effected by abstracting of the oxygen and sulphur bridging atoms, leaving less altered smaller molecules, compose-d essentially of hydrocarbons. This chemical reaction is illustrated by the following schematic equation:

wherein X is an oxygen or sulphur atom, and Me is the oxygen scavenging metal, R and R are the same radicals as defined before, and x-=m+n.

If, for economic reasons, a regeneration of the metal is desired, this can be done by well known processes in "ice which the spent metal oxides, containing also some amounts of unreacted coal and other carbonaceous residues from the invented process, are reduced at high temperatures back to the metal.

Another feature of my invention is to effect the desired depolymerization of the bituminous coal to mainly liquid products by avoiding the destructive cracking to gaseous and solid products, as it happens in coal gasificat-ion. This result is brought about in my invention by conducting .of the reaction at solid-solid interfaces and temperatures not higher than 400 C. and in most cases preferably at BOO-400 C.

Other novel features of this invention are to generate simultaneously by attrition grinding the necessary reaction temperature, also develop large and constantly renewed particle surfaces of the reacting coal and metal, provide high solid-solid particle pressure, thus promoting intimate closeness of the reactants.

A further object of my invention is to produce such useful liquid hydrocarbons as gasolines, jet fuels, rocket fuels, kerosines, gas and lubricating oils, high caloric heating oils and also valuable oxygenated and nitrogenated hydrocarbons like phenols, organic acids, pyridines, etc.

Further objects of my invention will be more clearly understood from the following description and examples:

The atoms of a solid, unlike those of a liquid or gas,

are constrained within narrow limits, and cannot present themselves for reaction with other atomic entities in an infinity of ways. Their chemical reaction depends on whether the solid is crystallinic or amorphous, this governing the velocity of material transport to the occurring reaction interface. I In the crystallinic state where the atoms are arranged in a perfect lattice, they are obeying the laws of symmetry and therefore, the solid reaction is expressed only by symmetry and not chemical changes of thevcrystal.

Bituminous coals are not crystallinic but rather pre-. dominantly amorphous solids with atoms much less rigidly fixed. Consequently, these atoms can move over many lattice distances with accompanying phenomena of nucleation on certain choice sites. The atom movements are, in addition, facilitated by many structural imperfections in the array of molecules and radicals comprising a large coal macromolecule.

The so-cal-led imperfections in reacting solid particles comprise molecular vacancies due to interstitial atoms and incidental foreign atom-s. They enable atoms to migrate and move around in the coal macr-omolecule in various ways: If an atom, at a normal lattice-site adjacent to a vacancy moves into that vacancy, the vacancy is conserved and may be used interstitially in succession of similar unit steps. This is called interstitial-vacancydiffusion, and being a pure random movement, it is enhanced by temperature and the presence of impurities. These impurities are defined as atoms, molecules and radicals not bound by molecular forces to the substrate coal com-. pound. Enhanced reactivity on the solid-solid interface is also intimately related to increased occurrence of pure vacancies and impurity vacancy complexes. 7 v

The existence of lattice vacancies and impurity vacancy complexes in bituminous coals was only recently proven by direct observation with the field ion microscope, also by methods of electron spin resonance. 'I'hese very new methods have shown the presence of foreign atoms interstitially trapped, the majority of which is situated in the proximity of the surface of the coal macromolecule.

Other newly developed analytical methods of coal'analysis have further clarified the basic structure of bituminous coals. It was found that an average bituminous coal attached alkyl side chains, these nuclei being held together partly by three dimensional CC groups, but predominantly by oxygen and sulphur atom bridges. Nitrogen atoms occur mainly inside of the heterocyclic rings, paraffin alkyl side chains and alicyclic hydrocarbon rings of N-carbon are randomly spread through the complex carbon macromolecule. Although the class of high bituminous coals from different sources may vary, it appears that long chain simple aliphatic and alicyclic hydrocarbon predominate in the coal. On the other hand, multiple polynuclear unsaturated ring structures poor in hydrogen and prone to further dehydrogenation to coke-like residues and gaseous hydrogen and methane apparently comprise only a minor constituent in the coal.

At high temperatures, at which known methods of coal carbonization or coal hydrogenation operate, the part played by point-molecular imperfections randomly moving inside the lattice of the coal macromolecule and to predominate over that played by surface imperfections, with the result that the solid solid interactions between a coal particle and another solid reactive particle tend to be relatively negligible. In mathematical terms, it can be said that for material transport by surface imperfections, A and E in the known Arrhenius equation: K=A- are both small, while for interstitial transport, which is signified by intermolecular decomposition reactions A and E are comparatively large. In other words, in bitu- 'rninous coal at higher temperature, therefore, the mechanisms of solid-solid interditfusion change in, favor of migration via interstitial imperfections culminating in many scission and repolymerization reactions liberating large amounts of low molecular gases and producing heavy tars and solid carbonaceous materials of low practical values.

In summing up the basic theoretical new idea of this invention, it is to predominantly utilize surface imperfections of bituminous coal for solid-solid selective reactions between oxygen and sulphur scavenging metal powders at temperatures as low as possible in order to keep A and E small in the above equation.

Preground coal, and preferably low priced coal fines are thoroughly mixed with any sufficiently friable metal possessing high heat of formation with oxygen and sulphur, preferably with preground or preformed particles of iron, aluminum, zinc, magnesium, titanium, manganese, copper, lithium, sodium, cadmium, potassium, cal cium, barium, etc., any alloys and/or mixtures thereof. This mixture is further ground at temperatures preferably not exceeding 400 C., until an aquilibrium is established in which the oxygen and sulphur bridges in the coal macromolecule become abstracted by the metal particles and converted into metal oxides and metal sulphides. As the majority of volatile bituminous coals contain less than of oxygen and sulphur combined, even when using high molecular metals like iron, the necessary amount of the metal will rarely amount to more than of the coal used. When the bridging oxygen and sulphur atoms are abstracted from the coal macromolecule it becomes fragmentized into a predominantly liquid mixture of various hydrocarbons containing some quantities of liquid nitrogenous and oxygenated hydrocarbons. I have found that during the above described chemical reaction, even at temperatures approaching 400 C., only small amounts of gaseous products are produced. This demonstrates the novelty of this invention; that a solid-solid reaction between particles of coal and an oxygen and sulphur scavenging metal which are involved in a mutually grinding reaction provides the only practical way to depolymerize coal to valuable liquid compounds. This grinding operation, combined with the exothermic reaction between the metal and the coal-bound oxygen and sulphur generates sufficient well distributed heat of reaction, and can be readily kept at the desired level by external cooling.

In the course of the invented solid-solid reaction, viscous, low volatile liquid products are produced which tend to adhere and lubricate the solid reacting surfaces of the coal and metal particles. This in many instances may counteract the intended solid-solid reaction and ultimately bring it prematurely to a standstill as further grinding will not produce any more of the desired liquid products.

It was found, and this is a further feature of this invention, that addition, during this reaction, of a low viscosity solvent like pyridine, its homologues, also preferably a mixture of pyridines with a distillate derived from this process, is very useful not only in keeping thereaction going to completion, but also by internal coolingheating, helps in the temperature control of the reaction.

After the reaction, the presence of this low viscosity solvent helps in the separation of the liquid coal depolymerization products from the solids (unreacted coal, metal oxides, metal sulphides, coal ash constituents, etc.).

Another feature of this invention, helping during this reaction to lower the viscosity of the liquid constituents, is to conduct the process under an internally produced pressure, by controlling the distilling-off of the low boiling products, as they are generated during the solidsolid coal depolymerization reaction. The reaction mass is finally centrifuged or filtered otf the solids.

The filtrate containing a mixture of hydrocarbons, phenolics and nitrogenated hydrocarbons, is processed by conventional methods, usually applied to distillates of low temperature coal carbonization, and is not the subject of this invention.

It is in the scope of this invention, however, to carry out this process not only batchwise but in a continuous way. For example, a properly proportionated mixture of the coal and metal powders is continuously fed from the top into an inclined or vertical grinder and tothe ground mass, the solvent is concurrently admixed. The solvent contacting intimately the ground material dissolves the generated coal depolymerization products, thus the coal and metal surfaces are freed for continued solid-solid reactions. Finally, the resulting slurry is discharged continuously into a centrifuge, filterpress, hydraulic or screw press, where it is separated into a solid and liquid phase.

The solid cake goes usually to a regeneration process in which the metal oxides are reduced at high temperatures with the predominantly contained carbonaceous materials back to the metal which consequently in a powder form is returned to the process. This operation is well known to experts and is not the subject of this invention.

Any good friable bituminous coal is useful in my process. The coal should be predried to the lowest possible moisture content; moisture will interfere with the reaction between the metal and the oxygen and sulphur atoms.

For economic reasons, in order to use as little as possible of the oxygen and sulphur scavenging metal, and on the other hand to obtain a high yield of liquid products from the coal, the coal should be rich in hydrogen and have a low oxygen, sulphur and ash content. These conditions are met by Boghead, Cannel, Splint and high, eventually medium volatile Bituminous Coals. In some instances Brown Coals may also be used.

I have found'that some Bituminous Coal, particularly those rich in sulphur, when processed as described therein, give a lower yield in coal depolymerization products that are shown by calculation. Consequently the solid cake from the process contains still considerable amounts of unreacted metal and coal particles.

I have further found that in these cases the calculated level of depolymerization can be reached by regrinding of the solid, solvent-wet filter cake obtained from the first grinding, after separation of the liquid phase. In some cases using brown and high bituminous coals as many as three and more grinding-separation cycles are practiced to achieve the highest utilization of the coal and metal input. 7

There follows the analysis of a number of domestic coals which I consider as preferred for my process: (Analysis made on dry basis.)

I. Cannel coal from Morgan, Ky.

(a) Volatile matter-50% (b) Fixed carbon38% (c) Total chemical analysis: Ash10.9%; sulphur 1.6%; oxygen-5.7%; nitrogen1.3%; hydrogen 6.6%; carbon73.9%

II. Splint coal from Kanawha, W. Va.

(21) Volatile matter30% (b) Fixed carbon-61% (c) Total chemical analysis: Ash9%; sulphur0.5%;

oxygen6.4%; nitrogen-4.4% hydrogen-5.0%; carbon77.7%

III. High volatile bituminous coal from Letchen, Ky.

(a) Volatile matter38% (b) Fixed carbon5 8% (c) Total chemical analysis: Ash-3 sulphur-0.6%;

oxygen-8.8%; nitrogen-4.8%; hydrogen5.8%; carbon-80.0%

IV. Medium volatile bituminous coal from Jefferson, Ala.

(a) Volatile matter27% (b) Fixed carbon68% (c) Total chemical analysis: Ash4.5%; sulphurl.6%;

oxygen-5.0%; nitrogen1.4% hydrogen-5 .5 carbon-82% The following three typical processing examples should illustrate the invention more clearly:

EXAMPLE 1 A high volatile bituminous coal from Letchen, Ky., analyzing as above, was used. Its friability, as determined by the Ball-Mill Method (ASTMD408-37T) was 70%. It was predried to a moisture content of 0.4% and in small pieces charged into a variable speed ball-mill equipped as follows: The closed ball-mill was built to operate at internal pressures up to 100 p.s.i. A heatingcooling mantle to preheat the interior of the mill with superheated steam up to 350 C.; or to cool it with water, if necessary, was used. The mill was connected with a condenser, receptacle, scrubber and a pressure valve leading into a gasometer. Thus the ball-mill served not only as a grinder but simultaneously as a pressure-reactor still. It was equipped with temperature and pressure regulating devices; also testing samples could be withdrawn during its operation.

The mill was charged with 86.5 weight parts of the coal and 13 weight parts of scrap cast iron powder of about 20 mesh. This amount of iron was calculated on the basis that it should scavenge all the sulphur and about 50% of the total oxygen contained in the coal. Analytical and structural studies of bituminous coals have shown that only 50% of the total oxygen analyzed, constituted bridging atoms which, according to this invention will be scavenged. The remaining oxygen constitutes mainly (OH) groups which give, after processing under this invention, various useful phenolic and organic acids. As a reaction starting catalyst, about 0.5 weight part of magnesium powder was then added. The mixture was ground in the closed ball-mill while the interior temperature was raised to about 300 C. by passing super heated steam through the heating mantle. After reaching this temperature, some pressure build-up inside the mill occurred showing that the solid-solid attrition grinding. reaction had been initiated. At thispoint the external heating was 300-350 C., with a reaction time of six hours during which a pressure of 30 p.s.i. was sustained, by removing through the pressure valve, the excess of volatile products. After passing through the cooler, the major part of the volatile was condensed, the remaining vapors and gases were scrubbed with an absorption oil, and the non-condensa-ble gases collected in a gasometer.

During this process the temperature is kept as low as possible, in order to prevent undesired decomposition-repolymerization reactions, which are so characteristic of the well-known process of low temperature gasification of coal, hydrogenation of coal and in particular for the high temperature coking of coal. This was done by injecting up to weight parts of a low viscosity solvent-coolant, which was a mixture of pyridine with a distillate fraction boiling from 200-3 60 C., and derived from this coal depolymerization process. The reaction was terminated after three hours when analysis of the mill content showed that an equilibrium between the reaction products was attained, without initiating the undesirable repolymerization processes. The produced slurry was then discharged from the mill and after recovering the solvent, added during the reaction, the following material balance was established:

A. Volatiles:

(1) Water condensable and washing oil absorbed vapors; (mainly hydrocarbons C4- and up) (2) Non-condensable hydrocarbon vapors and gases; (up to 0 NHz, also traces of H and CH4 B. Reaction slurry consisting of:

(l) Solids from filtration Mg0 I Unreacted Fe (as metal) Other ash constituents (SiOi etc.) 3

(b) Solid insoluble organic matter (unreacted coal, coke, asphaltenes, etc.) 15.1 (2) Organic liquids from filtration consistin 0f- Phenolic compounds Organic acids Basic org. compounds (pyridines, quinolines,

c. Hydroparbous, boiling up to 360 C. (gasomes Hydrocarbons boiling over 360 0. (diesel 0115. etc.) Residue (fuel oil) This result is much superior to any process of coal carbonization or even hydrogenation of a coal which analytically shows only 38% of volatile matter.

Another calculation of the above data indicates that from 86.5 weight parts of the high bituminous coal from Letchen, Ky., 13 weight parts of scrap cast iron powder (turnings, etc.) and 0.5 weight part of magnesium powder, we can obtain 37.5 weight parts of a hydrocarbon mixture and 15% of oxygen and nitrogen-containing organics. In addition the filtered off solids can be used as a valuable additive in an iron ore blast furnace or martin oven.

EXAMPLE 2 Flotation fines of a medium volatile bituminous coal from Jefferson, Ala., which analysis was shown before, were used. This almost worthless material is being recovered from spent flotation fluids by rotary filters made by Eimco Corporation, Salt Lake City, Utah, in the form of cakes A to A3 inch in thickness with a moisture content of about 30%. It must therefore be dried before processing to a moisture content not higher than 0.5%. 92.7 weight parts of this dried material are mixed with 7 weight parts of aluminum powder and 0.3 weight parts of metallic sodium, finely dispersed in a hydrocarbon. The

amount of aluminum was calculated in a small excess of the necessary quantity to scavenge completely not only all the sulphur but also all of the oxygen, thus avoiding the production of phenolics and organic acids, as demonstrated in Example 1. It is, however, understood that also lesser amounts of aluminum can be used when these oxygenated hydrocarbons are desired.

Further attrition grinding is preformed this time in a hammer-mill equipped in the same fashion as the ball-mill described in Example 1. The optimum processing. temperature was found here to be lower, not exceeding 275 C., and due .to the higher reactivity of aluminum, enhanced by the sodium catalyst, the reaction cycle was faster. Also more intense cooling of the mill was necessary in order to keep the exothermic reaction under control. After about three hours of the solid-solid reaction between the constantly renewed high surfaced coal and aluminum particles, the reaction was terminated. The content was discharged from the mill into a high speed Sharpless basket P-4000 Super-Conter Centrifuge. This separation of the reaction slurry into a solid cake and the filtrate was accelerated by using during the reaction of an appropriate amount of a low viscosity diluting oil derived from this coal liquification process. Another portion of this oil was used to wash the solid cake from the fluid portion, the remainder of the liquid being blown out with air. All volatile matter from the reaction were collected as described in Example 1. Finally, after subtracting the diluting oil, the reaction material balance was established as follows:

A. Volatiles:

(1) Water condensable and washing oil absorbed vapors: (Hydrocarbons C4 and up 11.0% (2) Noncondensable hydrocarbon vapors and gases: (up to 03-, NH; and traces of CH4) 1.

TotaL- 12. 0%

B. Reaction slurry consisting of:

(1) Solids from filtration- (a) Inorganic matter:

AI(OH)3 and A120; 5. 8%

A1804, traces of A1183 7.0

Unreacted aluminum 0.

Other ash constituents (NaSiO4, CaSO etc.) 5. 0 1 37 8. o

(b) Solid insoluble organic matter (unreacted coal,

coke, asphaltenes etc.) 12. 2

(2) Organic liquids from filtration consisting of:

Phenolic compounds It can be seen from above balance that from 92.7 weight parts of the coal not less than 68.5 weight parts of predominantly hydrocarbons were produced with a yield of 74%. This time only small quantities of oxygenated hydrocarbons were obtained.- The filtered off solids containing all the used aluminum predominantly as A1 0 mixed with approximately double of its amount carbonaceous material lends itself to known reduction process, in which the aluminum can be regenerated and returned into the process (US. Pat. 2,974,032). Thus, aluminum may be used repeatedly when combined with a regeneration operation.

EXAMPLE 3 In the following example there is depicted a preferred embodiment of the process of this invention. This process is depicted schematically in the accompanying drawing. A high volatile bituminous Cannel coal, analyzed as before indicated, from Morgan, Ky., was predried to a moisture content of 1.0%, and further preground to an average particle size of 20 mesh. Eighty weight parts of said coal were premixed with 20 weight parts of zinc dust, regenerated from a previous run, were fed continuously into grinder-reactor (A kept at an average temperature of 325 C. and pressure of 50 p.s.i. (FIG- URE 1). Into the center of this reactor-grinder, approximately 50 weight par-t of a solvent (S were introduced. Said solvent was derived from the same process, as a distillate fraction boiling from ZOO-360 C. The residence time of the mixture was kept at one hour. From (A the slurry passed to a screw-type solid-liquid separator (B where a filtrate (F was separated from a solid residue (R The filtrate (F went to a solvent regeneration and liquid coal depolymerization recovery unit. The solid residue (R was conveyed into reactorgrinder (A Here at a temperature of 350 C. and pressure of p.s.i. the solid residue (R was again ground in the presence of additional 50 weight parts of fresh solvent (S The ground mass passes to the screw separator (B where again a filtrate (F and a residue (R was obtained. Residue (R passed to reactor (A Here at 375 C. and a pressure of 100 p.s.i. it was finally ground in the presence of an additional 50 weight parts of fresh solvent (S This slurry passed into a screw-separator (B where a final solid residue (R and a filtrate (F was obtained. Filtrates (F and (F together with the previously made (F went to processing where the used solvents (S (S and (S were regenerated. The balance of the used solvents was regenerated from the residue (R by conventional means of vacuum and steam distillation, and returned into the process. The solvent-free residue went to a conventional regeneration of the used zinc dust by a retort distillation-reduction with coke.

Solvent-free filtrates (F F and F are processed into liquid coal depolymerization products. In addition, more volatile products are recovered from vapors and gases vented from A B A +B A +B as V V and V The material balance from processing of weight parts of the mentioned coal and 20 weight parts of zinc dust is as follows:

Volatiles: Percent 1) Water condensable and washing oil absorbed vapors; (mainly hydrocarbons C and up) 10.0 (2) Non-condensable hydrocarbon vapors and gases; (up to 0 NH and traces of CH 1.5

Total 11.5

Organic products from filtrates F and F consisting of:

(1) Phenolic and organic acids traces (2) Basic organic compounds; (pyridines,

quinolines, etc.) 5.0 (3) Hydrocarbons boiling up to 200 C. (gasolines etc.) 6.0 (4) Hydrocarbons boiling up to 360 C.

(kerosines, jet fuel, etc.) 10.0 (5) Hydrocarbons boiling over 360 C. (gas and diesel oils, etc.) 9.0 (6) Residue (fuel oil, etc.) 10.0

Total 40.0

Solid inorganic matter:

(1) ZnO, ZnS 27.0 (2) Unreacted zinc 0.5 Other ash constituents from the coal 11.0 'Solid organic matter: Unreacted coal, coke, asphaltenes, etc. 5.0

Total 43.5

It can be calculated from above material balance that from 80 weight parts of this coal and 20 weight parts of zinc dust not less than 50.5 weight parts of hydrocarbons and 5.0 weight parts of valuable nitrogenous bases were produced.

While these three examples, described in considerable detail, have been set forth above for purposes of illustration, the invention is not limited thereto. Various other modifications in processing, types of coal, kind of metal and mixtures thereof will be apparent in view of this disclosure to those skilled in the art. Such modifications are within the spirit and scope of the invention.

I claim:

1. A process for the depolymerization of bituminous coal to lower molecular weight fractions which comprises intimately mixing in a grinding operation solid particles of coal with friable particles of metals, said metals being present in an amount sufficient to react with a major portion of the chemically bonded oxygen and sulfur in the coal macromolecule, to produce lower molecular weight liquid organic fractions from the depolymerization of said coal while the metal is simultaneously converted to oxides and sulfides, and recovering the said lower molecular weight fractions by separating same from said metal oxides and sulfides.

2. A process for the polymerization of bituminous coal to lower molecular weight fractions which comprises intimately mixing in a grinding operation solid particles of coal with friable particles of metals, said metals being present in an amount sufficient to react with a major portion of the chemically bonded oxygen and sulfur in the coal macromolecule, to produce lower molecular weight, predominantly liquid organic fractions from the depolymerization of said coal while the metal is simultaneously converted to oxides and sulfides, and recovering the said lower molecular weight fractions by separating same from said metal oxides and sulfides.

3. A process for the depolymerization of bituminous coal to lower molecular weight fractions which comprises intimately mixing in a grinding operation at a temperature less than about 400 C. solid particles of coal with friable particles of metals, said metals being present in an amount sufficient to react with a major portion of the chemically bonded oxygen and sulfur in the coal macromolecule, to produce lower molecular weight, predominantly liquid organic fractions from the depolymerization of said coal while the metal is simultaneously converted to oxides and sulfides, and recovering the said lower molecular weight fractions by separating same from said metal oxides and sulfides.

4. A process for the depolymerization of bituminous coal to lower molecular weight fractions which comprises intimately mixing in a grinding operation at a temperature less than 400 C. at a pressure from 1 to atm. absolute solid particles of coal with friable particles of metals, said metals being present in an amount sufiicient to react with a major portion of the chemically bonded oxygen and sulfur in the coal macromolecule, to produce lower molecular weight, predominantly liquid organic fractions from the depolymerization of said coal while the metal is simultaneously converted to oxides and sulfides, and recovering the said lower molecular weight fractions by separating same from said metal oxides and sulfides.

5. A process for the depolymerization of bituminous coal to lower molecular weight fractions which comprises the sequential and repetitious steps of intimately mixing in a grinding operation solid particles of coal with friable particles of metals, said metals being present in an amount sufiicient to react with a major portion of the chemically bonded oxygen and sulfur in the coal macromolecule, to produce lower molecular weight, predominantly liquid organic fractions from the depolymerization of said coal while the metal is simultaneously converted to oxides and sulfides, and recovering the said lower molecular weight fractions by separating the same from said metal oxides and sulfides.

6. A process for the depolymerization of bituminous coal to lower molecular weight fractions which comprises the sequential and repetitious steps of intimately mixing in a grinding operation at a temperature less than about 400 C. solid particles of coal with friable particles of metals, said metals being present in an amount sufficient to react with a major portion of the chemically bonded oxygen and sulfur in the coal macromolecule, to produce lower molecular weight, predominantly liquid organic fractions from the depolymeriaztion of said coal while the metal is simultaneously converted to oxides and sulfides, and recovering the said lower molecular weight fractions by separating same from said metal oxides and sulfides.

7. A process for the depolymerization of bituminous coal to lower molecular weigh-t fractions which comprises the sequential and repetitious steps of intimately mixing in a grinding operation at a temperature less than about 400 C. and at a pressure from 1 to about 10 atm. absolute solid particles of coal with friable particles of metals, said metals being present in an amount sufiicient to react with a major portion of the chemically bonded oxygen and sulfur in the coal macromolecule, to produce lower molecular weight, predominantly liquid organic fractions from the depolymerization of said coal while the metal is simultaneously converted to oxides and sulfides, and recovering the said lower molecular weight fractions by separating same from said metal oxides and sulfides.

8. A process for the depolymerization of bituminous coal to lower molecular weight fractions which comprises intimately mixing in a grinding operation in the presence of a low viscosity solvent, solid particles of coal with friable particles of metals, said metals being present in an amount sulficient to react with a major portion of the chemically bonded oxygen and sulfur in the coal macromolecule to produce lower molecular weight, predominantly liquid organic fractions from the depolymerization of said coal while the metal is simultaneously converted to oxides and sulfides, and recovering the said lower metal oxides and sulfides.

9. A process for the depolymerization of bituminous coal to lower molecular weight fractions which comprises the sequential and repetitious steps of intimately mixing in a grinding operation in the presence of a low viscosity solvent, solid particles of coal with friable particles of metals, said metals being present in an amount sufiicient to react with a major portion of the chemically bonded oxygen and sulfur in the coal macromolecule, to produce lower molecular weight, predominantly liquid organic fractions from the depolymerization of said coal while the metal is simultaneously converted to oxides and sulfides, and recovering the said lower molecular weight fractions by separating same from said metal oxides and sulfides.

10. A process for the depolymerization of bituminous coal to lower molecular weight fractions which comprises intimately mixing in a grinding operation in the presence of a low viscosity solvent which is a distillate fraction obtained from the lower molecular weight fractions produced in the process, solid particles of coal with friable particles of metals, said metals being present in an amount sufiicient to react with a major portion of the chemically bonded oxygen and sulfur in the coal macromolecule, to produce lower molecular weight, predominantly liquid organic fractions from the depolymerization of said coal while the metal is simultaneously converted to oxides and sulfides, and recovering the said lower molecular weight fractions by separating same from said metal oxides and sulfides.

1-1. A process for the depolymerization o=f bituminous coal to lower molecular weight fractions which comprises intimately mixing in a grinding operation in the presence of a solvent comprised of pyridines and a low viscosity distillate fraction obtained from said process, solid particles of coal with friable particles of metals,

said metals being present in an amount sufficient to react with a major portion of the chemically bonded oxygen and sulfur in the coal macromolecule, to produce lower molecular weight, predominantly liquid organic fractions from the depolymerization of said coal while the metal is simultaneously converted to oxides and sulfides, and recovering the said lower molecular weight fractions by separating same from said metal oxides and sulfides.

12. A process for the depolymerization of bituminous coal to lower molecular weight fractions which comprises intimately mixing in a grinding operation solid particles of coal with friable particles of a metal alloy, said metal alloy being present in an amount sufficient to react with a major portion of the chemically bonded oxygen and sulfur in the coal macromolecule, to produce lower molecular weight predominantly liquid organic fractions from the depolymerization of said coal while the metal alloy is simultaneously converted to oxides and sulfides, and recovering the said lower molecular weight fractions by separating same from said metal oxides and sulfides.

13. A process for the depolymerization of bituminous coal to lower molecular weight tfractions which comprises intimately mixing in a grinding operation solid particles of coal with friable particles of metal and metal alloys, said metal and metal alloys being present in an amount suflicient to react with a major portion of the chemically bonded oxygen and sulfur in the coal macromolecule, to produce the lower molecular weight predominantly liquid organic fractions from the depolymerization of said coal while the metals and metal alloys'are simultaneously converted to oxides and sulfides, and recovering the said lower molecular weight fractions by separating the same from said metal oxides and sulfides.

14. The process of claim 2 wherein said metal is comprised primarily of iron.

15. The process of claim 2 wherein said met-a1 is comprised primarily of aluminum.

16. The process of claim 2 wherein said metal is comprised primarily of zinc.

17. The process of claim 2 wherein said metal is comprised primarily of copper.

18. The process of claim 2 wherein said metal is comprised primarily of an alloy of iron and manganese.

19. The product produced by the process of claim 2.

References Cited by the Examiner UNITED STATES PATENTS 1,296,367 3/1919 Cochran 23288 X 1,657,815 1/1928 Bates 208-8 X 1,922,491 8/1933 Mittasch et a1. 20 8-421 2,202,901 6/ 1940 Dreyfus 20'89 X 3,120,474 2/1964 Gorin et a1 20225 X u MORRIS O. WOLK, Primary Examiner.

JAMES H. TAYMAN, JR., Examiner.

DONALD S. LILLY, HERBERT A. BIRENBAUM,

Assistant Examiners. 

1. A PROCESS FOR THE DEPOLYMERIZATION OF BITUMINOUS COAL TO LOER MOLECULAR WEIGHT FRACTIONS WHICH COMPRISES INTIMATELY MIXING IN A GRINDING OPERATION SOLID PARTICLES OF COAL WITH FRIABLE PARTICLES OF METALS, SAID METALS BEING PRESENT IN AN AMOUNT SUFFICIENT TO REACT WITH A MAJOR PORTION OF THE CHEMICALLY BONDED OXYGEN AND SULFUR IN THE COAL MARCROMOLECULE, TO PRODUCE LOWER MOLECULAR WEIGHT LIQUID ORGANIC FRACTIONS FROM THE DEPOLYMERIZATION OF SAID COAL WHILE THE METAL IS SIMULTANEOUSLY CONVERTED TO OXIDES AND SULFIDES, AND RECOVERING THE SAID LOWER MOLECULAR WEIGHT FRACTIONS BY SEPARATING SAME FROM SAID METAL OXIDES AND SULFIDES. 